CFA8

Aero W&B: A Jim Dandy, Nifty iPhone/iPad Weight and Balance Application

September 2012

There are many weight and balance applications to wade through, and you need to be careful. I recently discovered AeroW&B, an aircraft weight and balance application available at the Apple App Store for $2.99. The app was developed for use with iPhones and iPads.

Key factors for a good weight and balance program include data entry for the passengers, fuel and baggage, and a graph that shows whether or not you are within the weight and center of gravity (CG) parameters for the entire flight. AeroW&B shines in meeting these requirements, and the app has filled a hole in my electronic flight bag.

The online manual/documentation is nonexistent, and if you like to install an app and then just poke around until you get it right, you may become frustrated—at least, that’s what happened to me.

Then I discovered a website with video tutorials walking you through all the inputs and menus for both platforms. (See the second entry under Resources for this link. —Ed.)

Questions and Answers – Engine Overspeeds

August 2012

Q: Dear Steve,

I have been flying my 1974 Cessna 182 a lot lately as I work toward getting my instrument rating. My other flying buddies have questioned the wisdom of using my airplane for my training—they tell me that I would save money if I rented a less complex airplane like the flight school’s 172—but I want to train in the airplane I’ll be flying in actual IFR conditions. So far, I think it’s been the right decision.

However (and there’s always a “however”) during one of my instrument approaches yesterday, my instructor suddenly told me to go around. In my haste to comply (I was under the hood), I quickly applied power. After we landed and reviewed the lesson, my instructor told me that I had jammed the throttle forward so fast that the engine RPM had gone past the tachometer redline.

His point was that I should never rush my actions when flying IFR, but I’m worried about my engine. Do you think I damaged it?

—Redline Buster

 

 A: Dear Buster,

First off, I want to commend you for pursuing your instrument rating. I believe the instrument rating is the graduate school of flying.

Now, back to your engine. Engine overspeeds are more common that most pilots realize. The most important thing pilots can do to eliminate overspeeds is to commit to making smooth power changes. Never cram the throttle forward, or jerk it back to the idle stop; idle to full throttle should take a minimum of three seconds. Count ‘em out…“one, one thousand; two, one thousand; three, one thousand.” Here’s why.

The RPM of the O-470R engine on your 182—an engine equipped with a constant speed propeller—is controlled by the prop governor that is working to balance the interplay between opposing forces.

Forces in the propeller that drive the blade angle to a flat pitch (high RPM) position in the hub during engine operation are (1) a low pitch spring in the propeller hub; and (2) the centrifugal twisting moment (CTM), a force generated during propeller rotation. The spring and CTM apply pressures that push a piston in the prop hub forward.

The forces that drive the blades to coarse pitch (low RPM) are (1) aerodynamic twisting force (think of lift generated by an airfoil); and (2) oil pressure from a small high-pressure oil pump inside the propeller governor. When governor oil pressure is directed to the forward side of the piston in the prop hub, the force is sufficient to drive the piston aft in the hub.

Your prop governor is mounted on a mounting pad located at the forward end of the right engine case half and is driven at crankshaft RPM (1.0:1 gear ratio).

The governor senses engine speed and responds to RPM changes by either directing oil under pressure to the hydraulic cylinder, or by releasing oil pressure from the cylinder. Changes in volume of the cylinder (by movement of the piston) changes blade angles. The amount of oil and direction of oil flow are controlled by the movement of a pilot valve in the governor.

The pilot valve is also positioned by opposing forces. A spring—called the speeder spring—pushes down on the pilot valve. Each time you adjust the prop control you are adjusting speeder spring tension. A set of flyweights in the governor rotate at crankshaft RPM to provide the forces that oppose the speeder spring down push. The position of the flyweights responds to changes in engine RPM. During stable cruise flight the opposing forces are balanced; therefore, the pilot valve moves only very slightly as it sends oil to, or vents oil from, the piston.

When the throttle is crammed forward to increase power, or pulled rapidly aft to decrease power, the pilot valve, the flyweights that control the pilot valve, the oil flow to the piston, the piston movement, and the blade angle changes aren’t able to change rapidly enough to strictly govern; therefore, an overspeed takes place.

Often pilots don’t really realize an overspeed has occurred because analog (moving needle) tachometers aren’t very accurate. These gauges were once accurate, but over the years the increase of friction in the needle movement and a lessening of the magnetic connection between the needle and the drive plate reduce accuracy.

Digital tachometers are very accurate. Horizon Instruments’ stand-alone P-1000 unit has an overspeed warning light. Full-featured engine monitors by JP Instruments, Electronics International, Flightline Systems and Insight Avionics all track and record engine RPMs, and can be programmed for RPM overspeed alerts. Engine monitoring sections of modern flat panel systems can also warn of and track the extent and duration of engine overspeeds.

HOW MUCH IS TOO MUCH?

The Teledyne Continental Motors Service Bulletin (SB) that spells out overspeed limitations is SB05-2. This SB was last updated in January 2005 and superseded M89-15.

The redline RPM for your O-470R is 2,600. The SB breaks overspeeds down into three categories. Each category (I, II and III) spells out the overspeed limits and the maintenance action required in each category.

Category I and Category II are further broken down by duration of overspeed. For instance, no maintenance is required in Category I if the time exceeding 2,900 RPM is less than 10 seconds. If over 10 seconds, maintenance requirements include draining the oil, removing and inspecting all oil screens and filters, and removing all valve covers and inspecting all “top end” components in accordance with the latest TCM service publication. In addition, an inspection for damage in the engine’s accessory drive section is conducted by checking for excessive backlash in the drives.

If no damage is found during this inspection, the bulletin requires the oil, screens and filters part of the inspection to be done again after five flight hours.

If an overspeed on an O-470R exceeds 3,200 RPM, Category II kicks in unless the overspeed is less than 10 seconds. If the overspeed exceeds 10 seconds, the likelihood of internal damage increases and all the cylinders need to be removed to check for damage.

It’s very unlikely that the momentary overspeed caused by your abrupt and rapid throttle “jamming” caused enough of an overspeed to require any maintenance action. But if you want to be extra safe, drain and screen the oil for contaminants, and remove and inspect the screen or filter. Based on your description of the event, you should be okay to continue flying.


Happy flying,

Steve

 

Know your FAR/AIM and check with your mechanic before starting any work.

 


Steve Ells has been an A&P/IA for 38 years and is a commercial pilot with Instrument and Multi-Engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as Associate Editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation (EllsAviation.com) and lives in Paso Robles, Calif. with his wife Audrey. Send questions and comments to .

 

 

Resources

Electronics International

buy-ei.com

 

Flightline Systems

ultra-fei.com

 

Horizon Instruments

horizoninstruments.com

 

Insight Instrument Corp.

insightavionics.com

 

JP Instruments

jpinstruments.com

 

Left Coast Pilot – Mortality and a Poker Run

August 2012

 

Six years ago, I opened my column with these words:
When I started flying actively about 10 years ago, I was warned that if I stuck with it, eventually I’d have to face the loss of a friend in an airplane crash.

Sad to say, it has happened again. What gives me pause is that this makes the fourth time in a little less than 10 years that a pilot with whom I’ve had a personal connection lost his life in an airplane crash.

The first was Steve Meissel, a fellow volunteer pilot with Liga International (“The Flying Doctors of Mercy”). Steve and three passengers collided with high terrain shortly after departure from Bishop, Calif. (KBIH) in 2003.

Three years later, I was told that Dave Mesenhimer, a co-owner of my flight school, was dead. He had been doing pattern work in an experimental aircraft when one of the wings came off.

Four years after that, we lost Chuck Swanson, a local pilot. Sadly, he died in the most inexplicable of these four accidents. For reasons that were never fully explained, his airplane began orbiting an area in the foothills of the Sierras near Angels Camp, Calif. and continued to circle until it ran out of gas and crashed.

Heading Bug – Aeronautical Innovation, Old Tech Space Flight and Paying Attention

August 2012

 

Your magazine was created in the world of monthly print publications and says August on the cover. Meanwhile, I write over Memorial Day weekend as a tropical storm named Beryl is coming ashore 50 miles or so east of where I sit, as winds of 11 on the Beaufort Wind Scale are recorded along the northern Florida coast.

It is raining harder and blowing more than I have ever seen in almost two years living in the Sunshine State. So it’s fitting that I tell you more about Sir Francis Beaufort of the Admiralty and his system of estimating wind strength—later.

 Two events on my mind, for widely different reasons, concern a new airplane design from Synergy Aircraft and the successful voyage of Space Exploration Technology (SpaceX) Corp.’s Dragon to supply the International Space Station (ISS).

Synergy Aircraft of Kalispell, Mont. is working on what could be called a “futuristic” project to build an airplane that uses what has been called “breakthrough” technology. With a 1/4-scale remote-control prototype flying, the company—family owned and run by John McGinnis—works out of a garage in that clichéd American tradition of inventiveness. The project has been getting lots of press (Wired, Gizmag, Designboom and more) outside of aviation. Praised by everyone from the EAA to the CAFE Foundation, there is reason those of us related to aviation might want to take notice.

Destination – Driggs, Ohio: An Ideal Fly-In Spot Just West of the Tetons

August 2012

 

WHAT MAKES A PERFECT FLY-IN DESTINATION? 
Of course, a good on-field restaurant is a great starting point, but going beyond the average hundred-dollar hamburger, it’s nice to have a museum or other on-field attraction. And if the field is located near one of North America’s top recreational spots, so much the better!

Driggs-Reed Memorial (KDIJ), just a mile or so west of the Idaho-Wyoming border, meets all these requirements. It has an upscale restaurant that goes well beyond the typical airport diner, a small but well-organized museum, and it’s just a short flight from Jackson Hole, Wyo.

Kate and I visited Driggs on the way home from our vacation trip to Jackson Hole last summer, but if you find yourself in the area, it’s an ideal location for a weekend fly-out.

Batteries: Producing the Juice That Makes ‘Em Go

August 2012

Batteries, like many things in aviation, are unexciting unless they malfunction. Then, they can be annoying, perplexing, or even dangerous. A few tips passed on to the people who own them can save a lot of headache, frustration and possibly, repair cost...

Note: Because nickel cadmium (NiCad) and lead-acid batteries differ in many important respects—and accepted practices for one type may destroy the other!—this article discusses flooded (vented, wet cell) lead-acid batteries. (Lithium-ion batteries, available soon in some new aircraft, have their own full-system requirements and are not covered here.)

Today’s batteries are similar in design to the first voltaic cells of two centuries ago, in that they exploit the chemical reactions that result between dissimilar metals when encouraged by an electrolyte. Each particular pack of metals can generate a given “pressure” of electricity, or voltage; the size of the pack largely determines the “volume” of electricity, or current (amperage), available at that voltage over a given time. Packing several cells into one case can increase voltage, amperage, or both.


Current aviation battery sizes translated directly from other disciplines. The -25 and -35 size batteries, for instance, were based on the 25 and 35 ampere-hour sized light-equipment batteries of the 1940s. (These sizes are still common in lawn tractors today.) They produced sufficient electricity for many airplanes, and they were small enough, so designers used these off-the-shelf components. As technology evolved inside, the case sizes endured. Other sizes were added as designers’ needs dictated.

Dry-charged batteries keep many years in their original, as-shipped condition. Opening the seals on these shortens life; and filling them with electrolyte (only up to the lower indicator; then follow the manufacturer’s specific directions) begins a battery’s service life.

Owner-pilots may service and replace their batteries without supervision by a mechanic (FAR 43, Appendix A). It’s up to mechanics to look for batteries that aren’t installed properly, and double-check the logs. (Resolution of discoveries must follow your mechanic’s own best practices. The key, though, is to first make the aircraft safe.)


CHARGE!

Keep the battery charged. It makes starting the engine easier and preserves the battery. Charged batteries fight off internal contaminants. Charged batteries don’t freeze. (Electrolyte in a fully-charged fresh battery may stay liquid to -80 degrees F or even lower; a dead battery’s electrolyte readily freezes at 20 degrees F.)

Battery life is degraded by remaining in a constantly partially-discharged state or by undercharging; by constant ambient temperatures below freezing or above 100 degrees F; or by overcharging, or by fast-charging in extremely low temperatures.

When removing a battery, disconnect the grounded side first; when installing, connect the ground last. This minimizes the opportunity for shorting the battery to the airframe or components through your tool.

For that same reason, and to minimize stress on the battery’s connectors, address the battery’s hold-downs after disconnecting, and before re-connecting the cables. Ensure that the hold-downs are secure, but remember that “too tight” does not add to security, and can cause annoying or even catastrophic problems.

Because batteries can boil or overflow, and because they create hydrogen during charging, it is wise to charge batteries outside the aircraft.

Overfilling a battery (even with deionized distilled water) dilutes the electrolyte, dropping the capacity and making the battery more susceptible to freezing. The good news is that, if you overfill with distilled water, the problem will eventually cure itself—if you do not tax the battery too much in the meantime. (To prevent this, add water after charging rather than before, unless the plates are exposed.) However, you can kill a battery fast if you charge it while the plates are not fully submerged; the exposed plates will oxidize, and that portion of the battery’s capacity will be forever lost.

When filling or topping off a battery, don’t spill any fluid—and remember that distilled water that washes dust and dirt into the cells when you’re filling them is a good conductor, and will drain the battery’s charge. Reinstall the battery only when it is clean and dry. As a general rule, refill with only distilled water. Don’t add electrolyte unless you’ve spilled electrolyte from the battery.

When the battery is cold, it does not produce as much power as when it is warm; and it doesn’t make as much power when it is hot as when it is warm. Charging, too, is most effective when the battery’s temperature is above freezing (and below about 100 degrees F).

When charging a battery, voltage is more critical than amperage. A battery will draw only as many amps as it needs, but too much voltage will ruin the battery. Your charger should never exceed 2.35 volts/cell (14.1 volts for a 12-volt battery; 28.2 for a 24-volt). Below-zero or 100-plus degrees F ambient temperatures may require some special considerations, and the manufacturer is the best source of that information.


WHAT CAN POSSIBLY GO WRONG?

Some certified installations employ a battery “sump” between the battery and the outside vent to neutralize the gases and any liquid that may be expelled. The chemicals in the sump (usually, sodium bicarbonate) can become saturated and insipid. They’re cheap; replacement can never be too frequent, and your aircraft’s finish will thank you.

Many aircraft systems become plugged, misrouted, damaged or saturated. All these conditions will enhance corrosion; some degrade the battery life, and some are dangerous.

Confined gases (such as the hydrogen produced during charging) can explode if exposed to sparks. It is not unheard of for a battery to explode when the starter is engaged: gases concentrate in the still air and the motor, a relay, or a loose connection provides the spark. Similarly, if the battery’s vent system is inop in flight, gases will accumulate near the battery, and a loose cable connection may provide the spark.


A COUPLE MYTHS, A COUPLE COMMON MISTAKES…

Myth 1: Batteries must never be placed on concrete, or their charge will be drawn out. That’s bunk. How could concrete draw a charge, when a metal battery box can’t? The myth probably originated when concrete dust was splashed on a battery in a rainstorm, either getting inside and diluting the electrolyte or shorting across the terminals in moisture on the outside. Batteries stored at factories and warehouses are still kept on wood pallets, but not because of any concrete allergies. They’re just easier to move when they are on pallets.

Myth 2: Batteries like to be discharged all the way before they are recharged. Not so. Discharging places stress on batteries, and removal of that stress (through recharging) lengthens the batteries’ lives.

Common Mistake 1: Over-tightening the contacts ruins lots of batteries. Electrons flow better through a snug contact than through one that’s partially broken. Further, a compromised battery post can work loose in flight, causing trouble—including fire.

Common Mistake 2: Topping off with tap water or electrolyte alters the chemistry of the battery. Tap water’s contaminants short the battery internally, and electrolyte changes the optimal pH of the mix, reducing voltage. Use deionized distilled water only, and clean the area around the caps before you remove them, so pollutants do not fall into the case.


…AND A COUPLE TIPS

Batteries should first be inspected at 600 hours or 12 months; after that initial inspection, the interval is halved. 100-hour inspection procedures also, of course, apply.

Always clean and dry a battery before reinstalling it.

When reinstalling, clean and dry the aircraft’s connections, too—and don’t forget to inspect the grounded end of the cable or strap.

When you see dark (brown or black) electrolyte, that’s a sign of a battery that’s nearing the end of its natural life. Put it out of its misery now, and it won’t fail you later.

Green or white “fur” around the terminals can be brushed and rinsed off using a solution of sodium bicarbonate, with the battery out of the airframe (to avoid shorting with the wire brush, or contaminating the battery compartment or sump). Don’t let any of the solution get into the battery!

Here’s a final tip: FAA AC 43.13-1B warns, “It is extremely dangerous to store or service lead-acid and NiCad batteries in the same area. Introduction of acid electrolytes into alkaline electrolyte will destroy the NiCad and vice versa.”

…And good practice with anything that contains lead (not to mention acid): always wear gloves when working around a battery, rinse your tools and wash your hands immediately after handling batteries, cable ends and posts.

 

Tim Kern, CAM, MBA, has authored features in over 40 aviation publications. He writes technical, publicity and expository pieces for several companies in the aviation industry, and gives his thanks to the folks at Concorde and Gill for their help in the preparation and proofing of this article. Kern is a private pilot with a seaplane rating, and is listed as the manufacturer (“with a lot of help!”) of an experimental aircraft. Send questions or comments to .

 

 

 

RESOURCES

Teledyne Battery Products/Gill

gillbatteries.com/maintenance.aspx 

 

Concorde Battery Corp.

concordebattery.com/otherpdf/ownermanual.pdf

 

AC 43-206 (Corrosion)

www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/be991fb487cd318586256ce100677049/$FILE/AC43-206part1.pdf

 

AC 43.13-1B (Aircraft Electrical Systems)

www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2011.pdf

 

Aging Aircraft Care and Maintenance

August 2012

Cessna manufactured approximately 145,000 single engine airplanes between 1946 and 1986. The average age of an aircraft in the Cessna fleet is 42 years; that translates to a 1970 model aircraft. The average airplane has an aluminum airframe that was certified under Civil Air Regulations using Civil Aeronautics Administration standards from the 1940s, ‘50s and ‘60s.

Certification requirements for legacy aircraft are similar to today’s certification strength requirements, but there are some major differences: the CAR standards contain no life limit or targeted requirement to detect metal fatigue as required under today’s certification standards.

No matter how carefully you treat one of these vintage airplanes, time and aircraft hours will translate into corrosion and fatigue cracks in any airframe. The best way to prepare for this eventuality is to create an inspection program that will identify these conditions and provide repairs/recommendations—before this type of wear compromises your safety.

Stratus: An In-Flight Weather Receiver

July 2012

Real-time, in-flight weather is not a new concept. Sirius XM and WSI have been providing it to pilots for years.

ADS-B, the key element in the United States government’s plan for the NextGen air traffic control system, has been in a long and slow development process. The service, which provides weather, traffic—and ultimately will provide clearances and other ATC communications—is now becoming available as the FAA pushes toward its full implementation by 2020.


ELECTRONIC WEATHER

The first element of NextGen to become available has been the weather products. But in order for pilots to take advantage of this service, they need an ADS-B receiver and a way to display the data.

Most readers would agree that the Apple iPad has emerged as the dominant choice for in-cockpit informational display. Gulfstream is certifying the iPad as an EFB on its new G650 ultra-high speed business jet; Jeppesen is aggressively pushing its chart service toward electronic formats; and companies like ForeFlight have developed apps for the iPad that are both easy to use and extremely cost-effective.

A few months ago, I did my first coast-to-coast flight using only an iPad for charts. The technology is amazing. In the confines of a General Aviation cockpit, it is wonderful to have all that material at your fingertips.

ForeFlight continues to expand its product with the introduction of in-flight weather. It has teamed up with a company called Appareo that has developed a self-contained ADS-B weather receiver—Stratus—and displays the product on the ForeFlight app on an iPad.

Questions and Answers – Anthology

July 2012

This month, we’ve compiled some of the most useful tips from Q&As published in Cessna Flyer over the last year. The questions and answers you’ll see here are abridged; refer to the original publication for complete information, including photos, drawings and company resources. —Eds.

 

JANUARY 2012
Q: Hi Steve,

My 1966 182 J doesn’t fly straight. How did my 182, which everyone swears shows no evidence of any major damage, get out of rig? What has to be done to fix it?

—Flying Sideways

A: Dear Sideways,

I’m not surprised at your report that your 182 is out of rig. In fact, I would bet that eight out of 10 Cessna singles that are more than 15 years old are out of rig.

The first step in rigging any single-engine Cessna is to set everything back to neutral. On your 182 this means the rudder, flaps, and ailerons; the nosegear centering block; the rudder cable whiffletree; the nosegear steering/rudder trim bungee length; the rear wing attach point eccentric bushings; the control wheels; the rudder pedals; the aileron bell cranks; the aileron push rod lengths; the flap actuating tube on the flap motor jackscrew, and the flap cable bell cranks; the flap, rudder and aileron cable tensions; and the flap actuating rods must be adjusted in accordance with the specifications in the aircraft service manual.

Push To Talk – Stuck on Stick and Rudder

July 2012

 The early days of flying were the toughest. In the early 20th century, people began taking to the skies at a time when humanity was still in the learning process about the pure physics of lift, weight, drag and thrust.  By trial and error, you might have learned things like adding a little top rudder to make sure you don’t overbank, or adding some elevator in the turn so as not to lose altitude. 

With this rudimentary knowledge, it’s not surprising that airplanes crashed at alarming rates. Talk to the really old-timers and you’ll find folks who can tell you about the 17 times they’ve had an engine quit or made a precautionary landing when things were looking tough. Stick and rudder skills were the core of every flight lesson.